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Flash‐induced electrogenic reactions in the SA(L223) reaction center mutant in Rhodobacter sphaeroides chromatophores
Author(s) -
Bibikov Sergei I.,
Bloch Dmitry A.,
Cherepanov Dmitry A.,
Oesterhelt Dieter,
Semenov Alexey Yu.
Publication year - 1994
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(94)80230-0
Subject(s) - rhodobacter sphaeroides , photosynthetic reaction centre , chromatophore , mutant , chemistry , flash (photography) , biophysics , photochemistry , biology , biochemistry , electron transfer , photosynthesis , physics , optics , genetics , gene
The charge transfer events in the SA(L223) reaction center mutant Rhodobacter sphaeroides chromatophores were investigated by direct electrometry. Besides the primary charge separation, the small stigmatellin‐sensitive electrogenic reaction due to the electron transfer from the primary to the secondary quinone acceptor in the reaction center complex was observed after the first flash. The second flash‐induced electrogenic phase of the secondary quinone protonation and subsequent electrogenic reactions of the cytochrome bc 1 complex were much slower than those in chromatophores of the wild type. It is suggested that replacement of Ser‐L223 by Ala impairs both specific proton‐conducting pathways leading to the secondary quinone Q B .